The design of a light guide plate originates from a liquid crystal display screen of a notebook computer. A light guide plate may transform a line light source into an area light source. The light guide plate takes an optical grade acrylic (PMMA) or PC as a substrate. Light enters the light guide plate from an incident surface of the light guide plate, and scatters at netted dots on the light guide plate so that the light is uniformly distributed. FIG. 1 illustrates a cross sectional structure of a light guide plate prepared by the existing technology. As viewed from the microstructure, circular or oval convex points are provided on the surface of the light guide plate. The outer diameter of the convex points is in a range between 40 μm and 60 μm. The light guide plate may be prepared by a hot pressing process.
In the process of realizing the traditional technology, the inventor found out that the following technical problems.
When preparing a light guide plate that is normal in size, a hot pressing device is required to have a pressure of up to six tons, and a hot pressing component of a hot pressing device is required to have a temperature of up to 140° C., in order to prepare the foregoing convex points that meet requirements. In this case, the service life of the hot pressing device is significantly decreased. Meanwhile, as the pressure increases and the temperature rises, the qualification rate of the light guide plate prepared is decreased by 10%.